USB (Universal Serial Bus) ports are present on most modern computers.
Several devices can be plugged into this bus, including mice and keyboards.
Support for USB mice is platform specific.

PS/2 mouse

The PS/2 mouse is
an intelligent device and may have more than three buttons and a wheel
or a roller. The PS/2 mouse is usually compatible with the original PS/2
mouse from IBM immediately after power up. The PS/2 mouse with additional
features requires a specialized initialization procedure to enable these
features. Without proper initialization, it behaves as though it were an
ordinary two or three button mouse.

Serial mouse

There have been numerous
serial mouse models from a number of manufacturers. Despite the wide range
of variations, there have been relatively few protocols (data format) with
which the serial mouse talks to the host computer.

The modern serial mouse
conforms to the PnP COM device specification so that the host computer
can automatically detect the mouse and load an appropriate driver. This
driver supports this specification and can detect popular PnP serial mouse
models on most platforms.

Bus mouse

The bus mouse connects to a dedicated
interface card in an expansion slot. Some older video cards, notably those
from ATI, and integrated I/O cards may also have a bus mouse connector.

The interface type of the mouse can be determined by looking at the connector
of the mouse. USB mice have a thin rectangular connector. PS/2 mice are
equipped with a small, round DIN 6-pin connector. Serial mouse have a D-Sub
female 9- or 25-pin connector. Bus mice have either a D-Sub male 9-pin connector
or a round DIN 9-pin connector. Some mice come with adapters with which
the connector can be converted to another. If you are to use such an adapter,
remember that the connector at the very end of the mouse/adapter pair is
what matters.

Depending on the X server version in
use, input device options may be set in either a xorg.conf file, or in the
configuration files read by the Hardware Abstraction Layer (HAL) daemon,
hald(8)
.

Please refer to xorg.conf(5)
for general configuration details and
for options that can be used with all input drivers. This section only
covers configuration details specific to this driver.

The driver can auto-detect
the mouse type on some platforms. On some platforms this is limited to
plug and play serial mice, and on some the auto-detection works for any
mouse that the OS's kernel driver supports. On others, it is always necessary
to specify the mouse protocol in the config file. The README.mouse document
contains some detailed information about this.

Not all protocols are supported on all platforms. The
"Auto" platform specifies that protocol auto-detection should be attempted.
There is no default protocol setting, and specifying this option is mandatory.

Option "Device" "string"

Specifies the device through which the mouse can
be accessed. A common setting is "/dev/mouse", which is often a symbolic
link to the real device. This option is mandatory, and there is no default
setting. The server may however attempt to probe some default devices if
this option is missing.

Option "Buttons" "integer"

Specifies the number
of mouse buttons. In cases where the number of buttons cannot be auto-detected,
the default value is 3. The maximum number is 24.

Option "Emulate3Buttons"
"boolean"

Enable/disable the emulation of the third (middle) mouse button
for mice which only have two physical buttons. The third button is emulated
by pressing both buttons simultaneously. Default: on, until a press of
a physical button 3 is detected.

Option "Emulate3Timeout" "integer"

Sets
the timeout (in milliseconds) that the driver waits before deciding if
two buttons where pressed "simultaneously" when 3 button emulation is enabled.
Default: 50.

Option "ChordMiddle" "boolean"

Enable/disable handling of
mice that send left+right events when the middle button is used. Default:
off.

Option "EmulateWheel" "boolean"

Enable/disable "wheel" emulation. Wheel
emulation means emulating button press/release events when the mouse is
moved while a specific real button is pressed. Wheel button events (typically
buttons 4 and 5) are usually used for scrolling. Wheel emulation is useful
for getting wheel-like behaviour with trackballs. It can also be useful
for mice with 4 or more buttons but no wheel. See the description of the
EmulateWheelButton, EmulateWheelInertia, XAxisMapping, and YAxisMapping
options below. Default: off.

Option "EmulateWheelButton" "integer"

Specifies
which button must be held down to enable wheel emulation mode. While this
button is down, X and/or Y pointer movement will generate button press/release
events as specified for the XAxisMapping and YAxisMapping settings. If
set to 0, no button is required and any motion of the device is converted
into wheel events. Default: 4.

Specifies the time in milliseconds the EmulateWheelButton must
be pressed before wheel emulation is started. If the EmulateWheelButton
is released before this timeout, the original button press/release event
is sent. Default: 200.

Option "XAxisMapping" "N1 N2"

Specifies which buttons
are mapped to motion in the X direction in wheel emulation mode. Button
number N1 is mapped to the negative X axis motion and button number N2
is mapped to the positive X axis motion. Default: no mapping.

Option "YAxisMapping"
"N1 N2"

Specifies which buttons are mapped to motion in the Y direction
in wheel emulation mode. Button number N1 is mapped to the negative Y axis
motion and button number N2 is mapped to the positive Y axis motion. Default:
no mapping.

Option "ZAxisMapping" "X"

Option "ZAxisMapping" "Y"

Option "ZAxisMapping"
"N1 N2"

Option "ZAxisMapping" "N1 N2 N3 N4"

Set the mapping for the Z axis
(wheel) motion to buttons or another axis (X or Y). Button number N1 is
mapped to the negative Z axis motion and button number N2 is mapped to
the positive Z axis motion. For mice with two wheels, four button numbers
can be specified, with the negative and positive motion of the second wheel
mapped respectively to buttons number N3 and N4. Note that the protocols
for mice with one and two wheels can be different and the driver may not
be able to autodetect it. Default: "4 5".

Option "ButtonMapping" "N1 N2 [...]"

Specifies how physical mouse buttons are mapped to logical buttons. Physical
button 1 is mapped to logical button N1, physical button 2 to N2, and so
forth. This enables the use of physical buttons that are obscured by ZAxisMapping.
Default: "1 2 3 8 9 10 ...".

Option "FlipXY" "boolean"

Enable/disable swapping the
X and Y axes. This transformation is applied after the InvX, InvY and AngleOffset
transformations. Default: off.

Option "InvX" "boolean"

Invert the X axis.
Default: off.

Option "InvY" "boolean"

Invert the Y axis. Default: off.

Option
"AngleOffset" "integer"

Specify a clockwise angular offset (in degrees)
to apply to the pointer motion. This transformation is applied before the
FlipXY, InvX and InvY transformations. Default: 0.

Option "SampleRate" "integer"

Sets the number of motion/button events the mouse sends per second. Setting
this is only supported for some mice, including some Logitech mice and
some PS/2 mice on some platforms. Default: whatever the mouse is already
set to.

Option "Resolution" "integer"

Sets the resolution of the device
in counts per inch. Setting this is only supported for some mice, including
some PS/2 mice on some platforms. Default: whatever the mouse is already
set to.

Option "Sensitivity" "float"

Mouse movements are multiplied by this
float before being processed. Use this mechanism to slow down high resolution
mice. Because values bigger than 1.0 will result in not all pixels on the
screen being accessible, you should better use mouse acceleration (see
man xset) for speeding up low resolution mice. Default: 1.0

Option "DragLockButtons"
"L1 B2 L3 B4"

Sets "drag lock buttons" that simulate holding a button down,
so that low dexterity people do not have to hold a button down at the same
time they move a mouse cursor. Button numbers occur in pairs, with the lock
button number occurring first, followed by the button number that is the
target of the lock button.

Option "DragLockButtons" "M1"

Sets a "master
drag lock button" that acts as a "Meta Key" indicating that the next button
pressed is to be "drag locked".

Option "ClearDTR" "boolean"

Enable/disable
clearing the DTR line on the serial port used by the mouse. Some dual-protocol
mice require the DTR line to be cleared to operate in the non-default protocol.
This option is for serial mice only. Default: off.

Option "ClearRTS" "boolean"

Enable/disable clearing the RTS line on the serial port used by the mouse.
Some dual-protocol mice require the RTS line to be cleared to operate in
the non-default protocol. This option is for serial mice only. Default: off.

Option "BaudRate" "integer"

Set the baud rate to use for communicating
with a serial mouse. This option should rarely be required because the
default is correct for almost all situations. Valid values include: 300,
1200, 2400, 4800, 9600, 19200. Default: 1200.

There are some other options
that may be used to control various parameters for serial port communication,
but they are not documented here because the driver sets them correctly
for each mouse protocol type.